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Evaluation of Potential Well Impacts From <br />The Proposed Nix Property Sand and Gravel Operation <br />Evaluation of the available saturated thickness at the wells identified in Table 5 indicates that <br />additional drawdown effects of less than 1 foot would reduce their available saturated thickness <br />by no more than approximately 5 percent. <br />For comparative purposes, WWE has estimated the maximum amount of drawdown that is <br />imparted on the aquifer (i.e., at the well itself) from a 15-gallon-per-minute {gpm) domestic well <br />and an estimated 1,000-gpm irrigation well using the Theis non-equilibrium equation. Assuming <br />a transmissivity of 200,000 gpd/ft and a specific yield of 0.2, a 15-gpm domestic well will create <br />0.2 feet of drawdown afrer 365 days at a distance of 1 foot from the pumping well. An additional <br />0.5 to 1 foot of decreased saturated thickness due to lake leveling will not diminish this well's <br />capacity to produce its permitted 15 gpm yield. Similazly, an irrigation well pumping 1,000-gpm <br />for 365 days under similaz aquifer conditions will produce a drawdown in the well of <br />approximately 10.6 feet at a distance of 1 foot from the pumping well. This drawdown is less <br />than half of the saturated thickness available at each of the irrigation wells in close proximity to <br />the Nix property. Similarly, 0.5 to 1 foot of additional drawdown at these wells due to lake <br />leveling will not diminish their capacity to produce their permitted yield. <br />' 5.0 CONCLUSIONS <br />Because of early concern with dry mining expressed by adjoining property owners and WWE's <br />initial evaluation of this alternative, Owens made the decision to use wet mining methods to <br />develop this resource. As such, WWE has conducted an evaluation of the potential well impacts <br />from the proposed wet mining of the Nix Sand and Gravel Operation. The conclusions reached <br />as a result of this evaluation aze as follows: <br />• Impacts to neighboring wells will occur from the leveling effects imparted on the sloping, <br />pre-mining groundwater surface resulting from the extraction of sand and gravel from below <br />the groundwater surface. <br />011-074.000 Wright Water Engineers, Inc. Page 9 <br />November 2001 <br />